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Thesis (M.S.)—University of Nebraska—Lincoln, 1972. Department of Agronomy.


Copyright 1972, the author. Used by permission.


Due to the need for more and higher quality pasture many farmers in the Great Plains have become interested in the management of cool season irrigated pastures the past few years.Smooth bromegrass is included in many irrigated pasture mixtures because of its productivity and persistence under heavy grazing. Smooth bromegrass is a leafy, rhizomatous, cool season grass native to Europe and Asia.It is adapted to the northern region of the United States with the major area of production being in the northwestern corn-belt.Smooth bromegrass is one of the primary grasses grown in grass-legume mixtures and can be grown on a number of different types of soil.It is noted for its winter hardiness, drought resistance and palatability.Management practices such as the use of fertilizer, irrigation and rotational grazing systems have increased the productivity and quality of pastures.

It is important to consider the morphological development of grasses to obtain maximum production from intensive management practices.Shoots of smooth bromegrass are produced in cycles and are formed from basal buds which pass through vegetative and reproductive stages.As shoots change from the vegetative to the reproductive stage the shoot apices (growing points) move rapidly upward and are susceptible to destruction by cutting or grazing.New tillers will not begin to develop until the growing points of primary shoots are destroyed or reach maturity.Therefore, yields and regrowth can be affected markedly by harvest management practices.Smooth bromegrass often experiences a summer dormancy period which is believed to be caused by the destruction of the growing points of the central meristems at a time when basal buds are not developing into new shoots.

This study was conducted to investigate the effects of cutting frequency and cutting height on the yield and regrowth of well managed irrigated smooth bromegrass.Total yield, rate of regrowth, and summer dormancy were the main items of interest. In addition, the percent digestible dry matter and percent protein were obtained from each cutting height and cutting frequency. Total nonstructural carbohydrates (TNC) were determined for each treatment after the last cutting of the season.

Advisor:L. E. Moser